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Optimize BLE mesh network for robustness and range (#314)

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- Fixed relay probability calculation for 2-node networks (0% relay needed)
- Added protocol ACKs to prevent unnecessary retransmissions
- Implemented MessageState for enhanced duplicate detection
- Added exponential backoff for collision avoidance
- Fixed duplicate sends for bidirectional connections
- Resolved packet ID generation issues using immutable fields only
- Implemented smart rate limiting with progressive throttling
- Removed unnecessary debug logging and fixed build warnings
- Optimized message routing to prevent flooding in small networks

Co-authored-by: jack <jackjackbits@users.noreply.github.com>
This commit is contained in:
jack
2025-07-24 19:49:37 +02:00
committed by GitHub
co-authored by jack
parent 498bb30d82
commit 492f90edd5
8 changed files with 831 additions and 172 deletions
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bitchat/Protocols/BinaryProtocol.swift
+17 -3
View File
@@ -19,11 +19,12 @@ extension Data {
}
// Binary Protocol Format:
// Header (Fixed 13 bytes):
// Header (Fixed 17 bytes):
// - Version: 1 byte
// - Type: 1 byte
// - TTL: 1 byte
// - Timestamp: 8 bytes (UInt64)
// - SequenceNumber: 4 bytes (UInt32)
// - Flags: 1 byte (bit 0: hasRecipient, bit 1: hasSignature)
// - PayloadLength: 2 bytes (UInt16)
//
@@ -34,7 +35,7 @@ extension Data {
// - Signature: 64 bytes (if hasSignature flag set)
struct BinaryProtocol {
static let headerSize = 13
static let headerSize = 17
static let senderIDSize = 8
static let recipientIDSize = 8
static let signatureSize = 64
@@ -77,6 +78,11 @@ struct BinaryProtocol {
data.append(UInt8((packet.timestamp >> (i * 8)) & 0xFF))
}
// Sequence number (4 bytes, big-endian)
for i in (0..<4).reversed() {
data.append(UInt8((packet.sequenceNumber >> (i * 8)) & 0xFF))
}
// Flags
var flags: UInt8 = 0
if packet.recipientID != nil {
@@ -165,6 +171,13 @@ struct BinaryProtocol {
}
offset += 8
// Sequence number
let sequenceData = unpaddedData[offset..<offset+4]
let sequenceNumber = sequenceData.reduce(0) { result, byte in
(result << 8) | UInt32(byte)
}
offset += 4
// Flags
let flags = unpaddedData[offset]; offset += 1
let hasRecipient = (flags & Flags.hasRecipient) != 0
@@ -240,7 +253,8 @@ struct BinaryProtocol {
timestamp: timestamp,
payload: payload,
signature: signature,
ttl: ttl
ttl: ttl,
sequenceNumber: sequenceNumber
)
}
}
bitchat/Protocols/BitchatProtocol.swift
+5 -2
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@@ -139,8 +139,9 @@ struct BitchatPacket: Codable {
let payload: Data
let signature: Data?
var ttl: UInt8
let sequenceNumber: UInt32 // New field for duplicate detection
init(type: UInt8, senderID: Data, recipientID: Data?, timestamp: UInt64, payload: Data, signature: Data?, ttl: UInt8) {
init(type: UInt8, senderID: Data, recipientID: Data?, timestamp: UInt64, payload: Data, signature: Data?, ttl: UInt8, sequenceNumber: UInt32 = 0) {
self.version = 1
self.type = type
self.senderID = senderID
@@ -149,10 +150,11 @@ struct BitchatPacket: Codable {
self.payload = payload
self.signature = signature
self.ttl = ttl
self.sequenceNumber = sequenceNumber
}
// Convenience initializer for new binary format
init(type: UInt8, ttl: UInt8, senderID: String, payload: Data) {
init(type: UInt8, ttl: UInt8, senderID: String, payload: Data, sequenceNumber: UInt32 = 0) {
self.version = 1
self.type = type
// Convert hex string peer ID to binary data (8 bytes)
@@ -171,6 +173,7 @@ struct BitchatPacket: Codable {
self.payload = payload
self.signature = nil
self.ttl = ttl
self.sequenceNumber = sequenceNumber
}
var data: Data? {
bitchat/Services/BluetoothMeshService.swift
+789 -157
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File diff suppressed because it is too large Load Diff
bitchatTests/EndToEnd/PrivateChatE2ETests.swift
+2 -1
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@@ -365,7 +365,8 @@ final class PrivateChatE2ETests: XCTestCase {
timestamp: packet.timestamp,
payload: encrypted,
signature: packet.signature,
ttl: packet.ttl
ttl: packet.ttl,
sequenceNumber: 1
)
self.bob.simulateIncomingPacket(encryptedPacket)
} catch {
bitchatTests/EndToEnd/PublicChatE2ETests.swift
+4 -2
View File
@@ -122,7 +122,8 @@ final class PublicChatE2ETests: XCTestCase {
timestamp: packet.timestamp,
payload: relayPayload,
signature: packet.signature,
ttl: packet.ttl - 1
ttl: packet.ttl - 1,
sequenceNumber: 1
)
// Simulate relay to Charlie
@@ -450,7 +451,8 @@ final class PublicChatE2ETests: XCTestCase {
timestamp: packet.timestamp,
payload: relayPayload,
signature: packet.signature,
ttl: packet.ttl - 1
ttl: packet.ttl - 1,
sequenceNumber: 1
)
// Relay to next hops
bitchatTests/Integration/IntegrationTests.swift
+6 -3
View File
@@ -197,7 +197,8 @@ final class IntegrationTests: XCTestCase {
timestamp: packet.timestamp,
payload: encrypted,
signature: packet.signature,
ttl: packet.ttl
ttl: packet.ttl,
sequenceNumber: 1
)
self.nodes["Bob"]!.simulateIncomingPacket(encPacket)
}
@@ -698,7 +699,8 @@ final class IntegrationTests: XCTestCase {
timestamp: packet.timestamp,
payload: encrypted,
signature: packet.signature,
ttl: packet.ttl
ttl: packet.ttl,
sequenceNumber: 1
)
self.nodes["Bob"]!.simulateIncomingPacket(encPacket)
}
@@ -805,7 +807,8 @@ final class IntegrationTests: XCTestCase {
timestamp: packet.timestamp,
payload: relayPayload,
signature: packet.signature,
ttl: packet.ttl - 1
ttl: packet.ttl - 1,
sequenceNumber: 1
)
for hop in nextHops {
bitchatTests/Mocks/MockBluetoothMeshService.swift
+4 -2
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@@ -73,7 +73,8 @@ class MockBluetoothMeshService: BluetoothMeshService {
timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
payload: payload,
signature: nil,
ttl: 3
ttl: 3,
sequenceNumber: 1
)
sentMessages.append((message, packet))
@@ -111,7 +112,8 @@ class MockBluetoothMeshService: BluetoothMeshService {
timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
payload: payload,
signature: nil,
ttl: 3
ttl: 3,
sequenceNumber: 1
)
sentMessages.append((message, packet))
bitchatTests/TestUtilities/TestHelpers.swift
+4 -2
View File
@@ -55,7 +55,8 @@ class TestHelpers {
recipientID: String? = nil,
payload: Data = "test payload".data(using: .utf8)!,
signature: Data? = nil,
ttl: UInt8 = 3
ttl: UInt8 = 3,
sequenceNumber: UInt32 = 1
) -> BitchatPacket {
return BitchatPacket(
type: type,
@@ -64,7 +65,8 @@ class TestHelpers {
timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
payload: payload,
signature: signature,
ttl: ttl
ttl: ttl,
sequenceNumber: sequenceNumber
)
}